Scroll fluid machine and assembling method thereof

ABSTRACT

The invention aims to provide a scroll fluid machine which has auxiliary cranks divided into two separate crank members connected by pressure fitting in the process of assembling of the scroll machine. Each of the auxiliary cranks for regulating the motion of the revolving scroll is divided into a revolving scroll side crank member and a stationary scroll side crank member, the crank members are configured such that one of the crank members can be pressed into the other crank member, and both of the crank members are connected to compose a one-piece auxiliary crank when both of the scrolls are assembled.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a scroll fluid machine forcompressing, expanding, or pressure feeding fluid and an assemblingmethod thereof.

DESCRIPTION OF THE RELATED ART

[0002] In a scroll fluid machine, three sets of mechanism for preventingrotation of the revolving scroll comprising auxiliary crank are placednear the periphery of the scrolls at equal circumferential spacing inorder to prevent rotation of the revolving scroll and allow it torevolve.

[0003] It is necessary that the mirror-surfaces of both of the revolvingand stationary scrolls are parallel to each other, since if they are notparallel to each other, hermeticity of the closed compression pocketformed by the wraps of the scrolls as the revolving scroll revolves isdamaged due to the deflection of the mirror-surfaces. Therefore, eachscroll should be supported by means of the auxiliary cranks of therotation preventing mechanisms so that both of the mirror-surfaces areparallel.

[0004] In Japanese Patent No. 2562581 is disclosed a scroll compressorwhich has three sets of mechanism for preventing rotation of therevolving scroll capable of adjusting the gap between the top surface ofwrap and the mating mirror-surface by rotating the double nuts whichdetermine the position of the auxiliary crank of each of the rotationpreventing mechanisms relative to the bearing provided in the bearinghousing of the stationary scroll.

[0005] Therefore, the gap between the top surface of wrap and the matingmirror surface is adjusted after the stationary scroll and revolvingscroll are assembled, and the adjusting must be performed for threeauxiliary cranks. which means the adjusting is intricate andtime-consuming.

[0006] If each of the auxiliary cranks is divided into two parts, astationary scroll side crank member and a revolving scroll side crankmember, one of the crank members being able to be pressed into the othercrank member to connect them to be compose a one-piece auxiliary crank,and both of the crank members installed respectively in the both of thescrolls are pressed into one-piece when both of the scrolls areassembled, said adjustment procedure of the gap after assembling both ofthe scrolls is eliminated. In this case, if both of the crank membersare so configured that the distance between the mirror-surfaces of bothof the scrolls can be adjusted by press-in depth of one of the crankmember into the other crank member, dimensional deviation of componentparts can be cancelled by the press-in depth.

[0007] When the dimensions of the component parts are accurate, thescrolls are assembled without undue deflection of the scroll plate bypreparing a standard auxiliary crank having the length corresponding tothe distance between the mirror-surfaces of both of the scrolls. But,when there is dimensional deviation of the component parts, the scrollplates may be deflected when both of the scrolls are assembled if saidlength of the standard auxiliary crank does not correspond to thedistance between the mirror-surfaces at all of the rotation preventionmechanisms.

[0008] The dimensional deviation varies depending on production lots, sothat many auxiliary cranks of different size (tolerance) must beprepared, resulting in complicated production control.

SUMMARY OF THE INVENTION

[0009] The present invention was made in light of the problem mentionedabove, and an object of the invention is to provide an auxiliary crankcomposed of a pair of crank members capable of being connected bypressing-in one of the crank members to the other crank member tocompose a one-piece auxiliary crank and a scroll fluid machine havingsaid auxiliary crank.

[0010] Another object of the present invention is to provide a scrollfluid machine which does not need the adjustment of the distance betweenthe mirror-surfaces after the revolving scroll and stationary scroll areassembled.

[0011] The present invention proposes a scroll fluid machine having arevolving scroll side connected to a stationary scroll side by means ofauxiliary cranks for regulating the motion of the revolving scroll,wherein each of said auxiliary crank comprises a revolving scroll sidecrank member and a stationary scroll side crank member, and both of thecrank members are connected by pressing one of the crank members intothe other crank member to compose a one-piece auxiliary crank.

[0012] Here, “revolving scroll side” and “stationary scroll side” refernot only to the revolving scroll and stationary scroll respectively.Referring to FIG. 1, said revolving scroll side includes, for example,the scroll 12 having a revolving scroll wrap 12 a and a mirror-surface12 c, and moving components attached to and revolving together with therevolving scroll 12.

[0013] Said stationary scroll side includes, for example, the stationaryscroll 11 having a stationary scroll wrap 11 a and a mirror-surface 11c, and the scroll housing 13 surrounding the revolving scroll 12 andfixed to the stationary scroll 11.

[0014] According to the present invention, the auxiliary crank isdivided into two crank members of the revolving scroll side andstationary scroll side, and both of the crank members are connected tocompose a one-piece crank by pressing one of the crank members into theother crank member.

[0015] Therefore, even if there is dimensional deviation of componentparts, the length of the auxiliary crank can be adjusted by adjustingthe press-in depth of one of the crank members into the other crankmember in accordance with the distance between the mirror-surfaces ofboth of the scrolls, that is, in accordance with the scroll wrap height.

[0016] To be more specific, when auxiliary cranks having differentlength are needed for maintaining the even distance between themirror-surfaces of both of the scrolls at all of the three rotationpreventing mechanisms, if the auxiliary cranks having the same length isused, deflection occurs in the scroll plates.

[0017] By adjusting the press-in depth of one of the crank members toconnect both of the crank members, dimensional deviation of thecomponent part can be absorbed or cancelled. Therefore, it is notnecessary to prepare auxiliary cranks of different dimension(tolerance), and dimensional deviation of component parts can becircumvented by adjusting the press-in depth.

[0018] In this way, auxiliary cranks each having the length capable ofcanceling dimensional deviation of component parts which differdepending on rotation preventing mechanisms and production lots arecomposed, resulting in a reduction of costs.

[0019] When scrolls with another scroll wrap height is to be assembled,the auxiliary cranks having the length corresponding to the wrap heightare needed. This is also acieved by adjusting press-in depth of one ofthe crank member into the other crank member to compose a one-pieceauxiliary crank.

[0020] It is an effective means of the present invention that pairs ofcrank members are selected in accordance with scroll wrap height and oneof each pair of crank members is pressed into the other crank member tocompose an auxiliary crank corresponding to the wrap height.

[0021] With the technical means like this, by preparing one or both ofthe crank members of various length and selecting the crank members, anauxiliary crank having the length corresponding to scroll wrap heightcan be composed.

[0022] It is also an effective means of the present invention that bothof the crank members are pressed into both side of a connectorpiece(spacer) to compose a one-piece auxiliary crank having the lengthcorresponding with scroll wrap height.

[0023] With the technical art like this, the length of the auxiliarycrank can be changed largely by changing the thickness of the spacer.

[0024] It is also an effective means of the present invention thatpress-in depth of at least one of the crank members into said connectorpiece(spacer) is varied to compose a one-piece auxiliary crank havingthe length corresponding with scroll wrap height.

[0025] With the technical art like this, it is not necessary to preparea variety of pair of crank members. It is enough to prepare at least oneof the crank members of various lengths and change said one of the crankmembers to correspond to scroll wrap height.

[0026] It is also an effective means of the present invention that abolt for fixing one of the crank members with the other crank member isprovided, and both of the crank members are fixed by said bolt tocompose auxiliary crank having the length corresponding with scroll wrapheight.

[0027] With the technical art like this, by preparing one of the crankmembers of various length and selecting the one which corresponds to theheight of the scroll wrap, it becomes unnecessary to prepare manyauxiliary cranks of various length and cost reduction is achieved.

[0028] The auxiliary crank according to the present invention ischaracterized in that it is composed of a pair of crank members capableof being connected by pressing in one of the pair of crank members, anda plurality of at least one of the crank members of different height areprepared so that said one of the crank members can be selected.

[0029] By preparing a plurality of one of the crank members of differentlength and selecting one of the crank members in order to correspond tothe height of the scroll wrap, it is not necessary to prepare manyauxiliary crank of different length, resulting in a reduction of costs.

[0030] Further, the method of assembling a scroll fluid machine ischaracterized in that each of the auxiliary cranks is divided in twocrank members, each crank member is mounted on the revolving side andstationary scroll side respectively, and both of the scrolls areassembled by shifting one of the scroll side in the direction of theaxis of the crank member so that one of the crank members is pressedinto the other crank member to be connected to compose a one-pieceauxiliary crank.

[0031] According to the invention, each of the auxiliary cranks isdivided into a revolving scroll side crank member and a stationaryscroll side crank member, and both of the crank members are connected inthe assembling process of the scroll machine by shifting the revolvingor stationary scroll side in the direction of the axis of the crankmembers. Thus a one-piece auxiliary crank is composed in the scrollmachine when both of the scrolls are assembled. Therefore, it is notnecessary to adjust the gap between the tip of the scroll wrap andmirror-surface after both of the scrolls are assembled. Said gap isalready adjusted when both of the scrolls are assembled, as the press-indepth is adjusted in the process of assembling. In this way, aplurality(three)of auxiliary crank are composed in the scroll machine bypressing one of the crank members into the other crank member in theprocess of assembling the scroll machine.

[0032] Therefore, according to the present invention, as the auxiliarycrank is divided into a revolving scroll side crank member and astationary scroll side crank member and both of the crank members areconnected by press fitting, dimensional deviation of components partscan be cancelled by the adjustment of the depth of insertion whenassembling the revolving and stationary scroll side. As a result,preparation of auxiliary cranks of various dimension is not necessary,auxiliary cranks can be composed in assembling process in accordancewith dimensional deviation of component parts which differs according toproduction lots, and cost reduction is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]FIG. 1 is a sectional view of an embodiment of the scroll fluidmachine of the present invention.

[0034]FIG. 2 is an illustration for explaining the method of assemblingthe revolving scroll side with stationary scroll side mounted withrevolving scroll side crank members and stationary scroll side crankmembers respectively.

[0035]FIG. 3 is another illustration for explaining the method ofassembling the revolving scroll side with stationary scroll side mountedwith revolving scroll side crank members and stationary scroll sidecrank members respectively.

[0036]FIG. 4 is a side view of an embodiment of the auxiliary crankconsisting of three component parts to be connected to compose anauxiliary crank including a partially sectional view.

[0037]FIG. 5 shows sectional views of two embodiments of the auxiliarycrank consisting of a pair of crank members to be connected to composean auxiliary crank.

[0038]FIG. 6 shows sectional views of another three embodiments of theauxiliary crank consisting of a pair of crank members to be connected tocompose an auxiliary crank.

[0039]FIG. 7 shows sectional views of still another three embodiments ofthe auxiliary crank consisting of a pair of crank members to beconnected to compose an auxiliary crank.

[0040]FIG. 8 shows an embodiment of the auxiliary crank consisting of apair of crank members provided with a tightening bolt.

[0041]FIG. 9 shows another embodiment of the auxiliary crank consistingof a pair of crank members provided with a tightening bolt.

[0042]FIG. 10 shows still another embodiment of the auxiliary crankconsisting of a pair of crank members provided with a tightening bolt.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] A preferred embodiment of the present invention will now bedetailed with reference to the accompanying drawings. It is intended,however, that unless particularly specified, dimensions, materials,relative positions and so forth of the constituent parts in theembodiments shall be interpreted as illustrative only not as limitativeof the scope of the present invention.

[0044]FIG. 1 is a sectional view of an embodiment of the scroll fluidmachine of the present invention. In the drawing, a scroll fluid machine1 is composed of a revolving scroll 12 having a wrap 12 a, a stationaryscroll 11 having a wrap 11 a meshing with said wrap 12 a, a scrollhousing 13 surrounding said revolving scroll 12 and fixed to saidstationary scroll 11, and a motor housing 14 incorporating a motor 2 todrive said revolving scroll 12.

[0045] The circular stationary scroll 11 is provided with a dischargehole 11 d in the center of the mirror-surface 11 c thereof, the hole 11d communicating with a outlet port 16. The stationary scroll 11 have astationary scroll wrap 11 a extending spirally outwardly from thevicinity of said discharge hole 11 d. A tip seal 34 made of fluorinecontained resin having self-lubricating property is received in thegroove defined in the tip of the wrap 11 a.

[0046] Three bearing housing bosses 11 b are formed equally spaced witha central angle of 120° near the periphery of the stationary scroll.Each bearing housing boss 11 b has an opening 11 g, in which ballbearings 8, 9 are received. The lower part 22 a of a crank member 22 isfit in the inner races of the bearing 8 and 9 and a bolt 38 is screwedin the female screw 22 b of the crank member 22 to fix the inner racesthereto via a washer 20.

[0047] The revolving scroll 12 has a revolving scroll wrap 12 aextending spirally to mesh with the stationary scroll wrap 11 a. A tipseal 35 made of fluorine contained resin having self-lubricatingproperty is received in the groove defined in the tip of the wrap 12 a.

[0048] Three bearing housing bosses 12 b are formed near the peripheryof the revolving scroll corresponding to those of the stationary scroll.Each bearing housing bosses 12 b has an opening 12 g, in which ballbearings 6, 7 are received.

[0049] The upper part 21 a of a crank member 21 is fit in the innerraces of the bearing 6 and 7 and a bolt 37 is screwed in the femalescrew 21 b of the crank member 21 to fix the inner races thereto via awasher 19.

[0050] The end part 21 c of the crank member 21 of the revolving scroll12 side is pressed into the hole 22 c of the crank member 22 of thestationary scroll 11 side to form an auxiliary crank with the centeraxis of the crank member 22 and that of the crank member 21 offset tocompose a rotation preventing mechanism 10.

[0051] The revolving scroll 11 has a wall surrounding the stationaryscroll wrap 11 a and a dust seal 36 is received in the groove defined inthe tip of the wall, the tip surface facing the mirror-surface 11 a ofthe stationary scroll.

[0052] A bearing housing boss 12 d is formed on the other side of themirror-surface 12 c of the revolving scroll 12 in the housing hole ofwhich is fitted a ball bearing 25.

[0053] The scroll housing 13 having a inlet port of fluid is providedwith a bearing housing boss 13 d which is fitted a ball bearing 15. Inside the scroll housing 13 and the motor housing 14 is mounted arotation shaft 3 having a rotor 18, and a stator 17 surrounding therotor 18 is attached to the motor housing 14 which is fixed to thescroll housing 13 by means of bolts 23. The stationary scroll 11 isfixed to the scroll housing 13 by means of bolts 24.

[0054] An end side of the rotation shaft 3 is supported for rotation bythe motor housing 14 via a ball bearing 26 and the other end side 3 a issupported for rotation by a ball bearing 5 in the housing hole 13 d ofthe scroll housing 13.

[0055] An offset crank member part projecting from the end surface ofsaid end side 3 a of the rotation shaft 3 is fit in the inner race ofthe ball bearing 25.

[0056] In the scroll fluid machine 1 composed as described above, therevolving scroll 12 revolves as the rotation shaft 3 rotates, fluid issucked from the inlet port 15 of the scroll housing 13 to be taken intothe closed pocket formed by the wraps of the revolving and stationaryscrolls. The closed pocket is transferred toward center reducing in itsvolume as the revolving scroll revolves and the fluid in the pocket iscompressed to be discharged from the discharge hole 11 d and then letout from the outlet port 16.

[0057] Next, the method of pressing the revolving scroll side crankmember 21 into the stationary scroll side crank member 22 will beexplained with reference to FIG. 2.

[0058] Referring to FIG. 2, three bearing housing bosses 12 b areprovided near the periphery of the revolving scroll 12 equally spacedwith center angle of 120° as mentioned before. Similarly, the stationaryscroll is provided with three bearing housing bosses 11 b correspondingto the three bearing housing bosses 12 b of the revolving scroll 12.

[0059] Marks 11 e are inscribed on the stationary scroll to show theposition of the openings of the bearing housing bosses 11 b. One of themarks 11 e is on the straight line passing the centers of the stationaryscroll and the opening of one of the nearing housing bosses 11 b, othertwo marks are on the lines parallel to said straight line passing thecenters of the openings of the other bearing housing bosses 11 b.

[0060] The stationary scroll side crank member 22 has on its top thehole 22 c, the center axis of which is offset from the center axis ofthe lower part 22 a. A mark 22 e is inscribed on the stationary scrollside crank member 22 on the straight line extending from the center ofthe lower part 22 a (see FIG. 1) passing the center of the hole 22 c.The stationary scroll side crank members 22 are rotated so that themarks 22 e coincide with the marks 11 e respectively. In this state, therevolving scroll is positioned so that the end part 21 c (see FIG. 1) ofeach crank member 21 matches to the opening 22 c of the crank member 22,then the revolving scroll 11 is pressed down so that the lower end partof each crank member 21 is pressed into the opening 22 c of each crankmember 22.

[0061] The existence of the hole 21 d in the crank member 22 favors thepressing-in of lower end part of the crank member 21 into the opening 22c of the crank member 22.

[0062] Next, the method of pressing the revolving scroll side crankmember 21 into the stationary scroll side crank member 22 will beexplained with reference to FIG. 3. The point of difference from FIG. 2is that assembling is performed with the motor 2 accommodated in themotor housing 14 and scroll housing 13, and with the revolving scrollattached to the rotation shaft 3 of the motor.

[0063] In this case also each of the marks 22 e are brought to coincidewith each of the marks 11 e respectively. Then the rotation shaft 3 isset to its maximum offset position toward right in the drawing.

[0064] The revolving scroll is positioned so that the lower end part 21c of each crank member 21 matches to the opening 22 c of each crankmember 22, then pressing force is applied on the motor housing 14 nearthe periphery so that the lower end part 21 c of each crank member 21 ispressed into the opening 22 c of each crank member 22. The pressingforce applied on the motor housing is transmitted to the scroll housing13, and the wall of the scroll housing deflects to contact the top ofeach bolt 37 which fixes the crank member 21 to the bearing 6, 7, andthe revolving scroll side crank member 21 are pressed into the openings22 c of the stationary scroll side crank member 22.

[0065] The press-in depth of each of the crank members 21 into the hole22 c of each of the crank members 22 can be determined by the push-downdistance of the motor housing 14. Since the distance between themirror-surface of the revolving scroll and that of the stationary scrollcan be adjusted by controlling said press-in depth, the adjusting issimple compared with the prior art of adjusting by means of the doublenuts at three places, and accurate adjusting is possible.

[0066] It is preferable that the pressing force is applied on the topnear the periphery 14 a immediately above the circumferential wall 14 bof the motor housing 14, and that the bolt 37 are located immediatelybelow the circumferential wall 13 b of the scroll housing 13 with a gapof about 0.5˜1 mm between the top of the bolt 37 and the inner uppersurface 13 b of the scroll housing 13. Further, it is preferable thatthe clearance between the top face 3 e of the rotation shaft 3 and thebottom surface 12 h of the bearing housing 12 d of the revolving scroll12 is larger than the press-in depth of the crank member 21 into theopening 22 c of the crank member 22.

[0067] As a result, the top face 3 e of the rotation shaft 3 does notcontact with said bottom surface 12 h when pressing force is applied onthe periphery part 14 a of the motor housing 14. The pressing force istransmitted through the circumferential wall 14 b of the motor housing14 to the circumferential wall 13 b of the scroll housing 13, then tothe bolt 37 of the crank member 21, so that undue stress which inducesdamage of the motor does not act on the motor.

[0068] According to the embodiment, each of the auxiliary cranks isdivided into a revolving scroll side crank member and a stationaryscroll side crank member, and both of the scrolls can be assembled sothat the mirror-surface of the revolving scroll is parallel to that ofthe stationary scroll without the necessity of adjusting the threeauxiliary cranks by means of double nuts after the assembling of thescrolls by pressing the revolving scroll side crank member into thestationary side crank member with the press-in depth adjusted.

[0069] Another embodiment which is effective likewise will be explainedhereunder.

[0070]FIG. 4 is a side view of an embodiment of the auxiliary crankconsisting of three component parts to be connected to compose anauxiliary crank including a partially sectional view. A revolving scrollside crank member 31 and a stationary scroll side crank member 32 arepressed into a connecting ring 28 to be assembled into an auxiliarycrank. The shaft part 31 a of the crank member 31 is inserted into thebearings of the revolving scroll and the shaft part 32 a of the crankmember 32 is inserted into the bearing of the stationary scroll. Theshaft part 31 c of the crank member 31 is pressed into the opening 28 cof the connecting ring 28 and the shaft part 32 d of the crank member 32is pressed into the opening 28 d of the connecting ring 28 when both ofthe scrolls are assembled.

[0071] The length of the auxiliary crank cab be adjusted by preparingthe connecting rings 28 of various height.

[0072] The opening 28 c and 28 d may be communicated to form a throughhole and the press-in depth of the crank member 31, 32 can be adjustedto adjust the length of the auxiliary crank.

[0073] A female screw thread may be provided in the center of each ofthe crank member 31 and crank member 32 for fastening bearings by meansof a bolt.

[0074] The edge 28 a and 28 b of the opening 28 c and 28 d respectivelyof the connecting ring 28 are preferable to be rounded ortaper-chamfered. The edge 31 b and 32 d of the shaft part 31 c and 32 dof the crank member 31 and 32 respectively are preferable to be taperedor rounded. By tapering or rounding like this, the crank members can beeasily pressed-in even when the center axis of the shaft part to bepressed-in does not coincide accurately with that of the opening forreceiving the shaft part.

[0075]FIG. 5 shows sectional views of two embodiments of the auxiliarycrank consisting of a pair of crank members to be connected to composean auxiliary crank. FIG. 5(a) shows the case the top edge 39Ad of theshaft part 39Ac to be pressed-in of the revolving scroll side crankmember 39A is rounded so that the shaft part 39Ac can be easily pressedinto the opening 40Ac of the stationary scroll side crank member 40A.The shaft part 39Aa of the crank member 39A is inserted into thebearings of the revolving scroll, and the shaft part 40Aa of the crankmember 40A is inserted into the bearings of the stationary scroll.Female screw thread 39Ab and 40Ab is cut in the center of the shaft part39Aa and 40Aa respectively for fastening the bearings by means of abolt.

[0076]FIG. 5(b) shows the case the top edge 39Bd of the shaft part 39Bcto be pressed-in of the revolving scroll side crank member 39B istaper-chamfered instead of being rounded as is the case with FIG. 5(a).

[0077] By tapering or rounding the top edge of the shaft part of therevolving scroll side crank member like this, the crank member can beeasily pressed into the opening 40Ac of the stationary scroll side crankmember even when the center axis of the shaft part 39Bc does notcoincide accurately with that of the opening 40Ac.

[0078]FIG. 6 shows sectional views of another three embodiments of theauxiliary crank consisting of a pair of crank members to be connected tocompose an auxiliary crank. In all of FIG. 6(a), (b), (c), the edge ofthe opening 40Bc of the stationary scroll side crank member 40B ischamfered in a tapered shape (40Bd), and the configuration of the crankmember 40B is the same as that of the crank member 40A of FIG. 5 inother than that point.

[0079] Concerning the revolving scroll side crank member, the top edgeof the shaft part 39Cc to be pressed-in is not rounded ortaper-chamfered in the case of FIG. 6(a), but as the edge of the opening40Bc of the crank member 40B is taper-chamfered, the shaft part 39Cc canbe pressed into the opening 40Bc with relative ease. The configurationof the crank member 39C is the same as that of the crank member 39A ofFIG. 5.

[0080] In the case of FIG. 6(b), the crank member 39B is used and thetop edge 39Bd of the shaft part 39Bc to be pressed-in istaper-chamfered, so the shaft part 39Bc can be easily pressed into theopening 40Bc.

[0081] In the case of FIG. 6(c), the crank member 39B is used and thetop edge 39Ad of the shaft part 39Ac to be pressed-in is rounded, so theshaft part 39Ac can be easily pressed into the opening 40Bc.

[0082]FIG. 7 shows sectional views of still another three embodiments ofthe auxiliary crank consisting of a pair of crank members to beconnected to compose an auxiliary crank. In all of FIG. 7(a), (b), (c),the edge of the opening 40Cc of the stationary scroll side crank member40C is rounded(40Cd). and the configuration of the crank member 40C isthe same as that of the crank member 40A of FIG. 5 in other than thatpoint.

[0083] Concerning the revolving scroll side crank member, the crankmember 39C of FIG. 6 is used as revolving scroll side crank member andtop edge of the shaft part 39Cc to be pressed-in is not rounded ortapered in the case of FIG. 7(a), but as the edge of the opening 40Bc ofthe crank member 40B is rounded (40Cd), the shaft part 39Cc can beeasily pressed into the opening 40Bc.

[0084] In the case of FIG. 7(b), the crank member 39B is used and thetop edge 39Bd of the shaft part 39Bc to be pressed-in istaper-chamfered, so the shaft part 39Bc can be easily pressed into theopening 40Bc.

[0085] In the case of FIG. 7(c), the crank member 39A is used and thetop edge 39Ad of the shaft part 39Ac to be pressed-in is rounded, so theshaft part 39Ac can be easily pressed into the opening 40Bc.

[0086] By taper-chamfering or rounding the top edge of the shaft part tobe pressed-in or the edge of the opening to receive the shaft part asshown in FIGS. 5,6, and 7, the shaft part to be pressed-in can be easilypressed into the opening to receive the shaft part even if the centeraxis of the shaft part does not coincide accurately with that of theopening.

[0087]FIG. 8 shows an embodiment of the auxiliary crank consisting of apair of crank members provided with a tightening bolt. FIG. 8(a) showsone of the crank member in a side view and the other crank member in asectional view.

[0088] The stationary scroll side crank member having the shaft part42Aa to be inserted into the bearings of the stationary scroll is formedinto a mushroom-like shape having a cap and a stem, a hole 42Ac isformed in the cap, the center axis of the hole being offset from that ofthe stem. A slit 42Ag is cut in the cap along the center line passingthe centers of the stem 42Aa and hole 42Ac. A screw hole 42Ae with spotfacing 42Af is provided perpendicular to the slit 42Ag in order tofirmly clasp the shaft part 41Ac of the revolving scroll side crankmember 41A by tightening the bolt 33 after it is inserted into the hole42Ac.

[0089]FIG. 9 shows another embodiment of the auxiliary crank consistingof a pair of crank members provided with a tightening bolt.

[0090] The point different from FIG. 8 is that a slit 42Bg is cut beyondthe center axis of the shaft part 42Ba through the cap and thestem(shaft part 42Ba), although in the case of FIG. 8 the slit 42Ag iscut only in the cap.

[0091] Therefore, when the material and geometry are the same as thoseof FIG. 8, weaker tightening of the bolt 33 than the case of FIG. 9 isallowed for firmly clasping the shaft part 41Ac of the revolving scrollside crank member 41A after it is inserted into the hole 42Ac.

[0092]FIG. 10 shows still another embodiment of the auxiliary crankconsisting of a pair of crank members provided with a tightening bolt.

[0093] In this case, a lateral slit 42Ch reaching near the center axisof the stem(shaft part 42Ca) is cut in the cap of the crank member 42Cin addition to a longitudinal slit 42Cg.

[0094] Therefore, when the material and geometry are the same as thoseof FIG. 8 and FIG. 9, still weaker tightening of the bolt 33 than thecase of FIG. 8 and FIG. 9 is allowed for firmly clasping the shaft part41Ac of the revolving scroll side crank member 41A after it is insertedinto the hole 42Ac.

[0095] It is allowable that the revolving scroll side crank member ispressed into the hole of the stationary scroll side crank member withthe bolt 33 tightened beforehand.

[0096] A female screw thread may be provided in both of the crankmembers in the center of the shaft part to be inserted into the bearingsfor fastening the bearings by means of a bolt.

[0097] It is possible in the embodiments of FIGS. 4˜10 that aspacer(connector piece) is provided between both of the crank memberswhich are pressed into both side of the spacer and the length of theauxiliary crank can be adjusted in accordance with the distance betweenthe mirror-surfaces of both of the scrolls.

[0098] It is also suitable to apply an adhesive agent at least to theshaft part to be pressed-in or to the hole to receive the shaft part inorder to reinforce the connection between the crank members.

[0099] Although the bearing housings bosses 12 b are formed integralwith the revolving scroll 12 as shown in FIG. 1, it is possible toprepare the bearing housing bosses separately and attach to therevolving scroll, for example, by means of bolts. In this specification,“revolving scroll side crank member” includes the crank member in bothof the above cases.

[0100] Further, although the bearing housing bosses 11 b are formedintegral with the stationary scroll as shown in FIG. 1, it is possibleto form the bearing housing bosses in the scroll housing 13 whichsurrounds the revolving scroll and is fixed to the stationary scroll. Inthis specification, “stationary scroll side crank member” includes thecrank member in both of the above cases.

1. A scroll fluid machine having a revolving scroll side connected to a stationary scroll side by means of auxiliary cranks for regulating the motion of the revolving scroll, wherein each of said auxiliary crank comprises a revolving scroll side crank member and a stationary scroll side crank member, and both of the crank members are connected by pressing one of the crank members into the other crank member to compose a one-piece auxiliary crank.
 2. The scroll fluid machine according to claim 1, wherein pairs of crank members are selected in accordance with scroll wrap height and one of each pair of crank members is pressed into the other crank member to compose a one-piece auxiliary crank having the length corresponding with the wrap height.
 3. The scroll fluid machine according to claim 1, wherein both of the crank members are pressed into both side of a connector piece(spacer) to compose a one-piece auxiliary crank having the length corresponding with scroll wrap height.
 4. The scroll fluid machine according to claim 3, wherein press-in depth of at least one of the crank members into said connector piece(spacer) is varied to compose a one-piece auxiliary crank having the length corresponding with scroll wrap height.
 5. The scroll fluid machine according to claim 1, wherein a bolt for fixing one of the crank members with the other crank member is provided, and both of the crank members are fixed by said bolt to compose an auxiliary crank having the length corresponding with scroll wrap height.
 6. The scroll fluid machine according to claim 1, wherein the auxiliary crank is composed of a pair of crank members capable of being connected by pressing in one of the pair of crank members, and a plurality of at least one of the crank members of different length are prepared so that said one of the crank members can be selected.
 7. A method of assembling a scroll fluid machine having a revolving scroll side connected to a stationary scroll side by means of auxiliary cranks for regulating the motion of the revolving scroll, wherein each of the auxiliary cranks is divided in two crank members, each crank member is mounted on the revolving side and stationary scroll side respectively, and both of the scrolls are assembled by shifting one of the scroll side in the direction of the axis of the crank member so that one of said crank members is pressed into the other crank member to be connected to compose a one-piece auxiliary crank. 